The present invention relates generally to millimeter-wave cascode amplifiers, and more particularly, to a gain boosting technique for use with millimeter-wave cascode amplifiers.
The increasing demand for short range, low-cost and high data rate networking solutions drives the research for silicon-based implementation of millimeter-wave (MMW) front end in 59-64 GHz world-wide license-free frequency band. Such applications target multi-gigabit wireless data transfer between hard disks, storage devices, MP3 players, high definition television receivers, and the like. Historically, III-V semiconductors (GaAs, InP) were used to implement millimeter-wave integrated circuits. See K. Lai, et al., “A high performance and low DC power V-band MIMIC LNA using 0.1 μm InGaAs/InAlAs/InP HEMT technology,” IEEE Microwave and Guided Wave Letters, Vol. 3, No. 12, pp. 447-449, December 1993; S. E. Gunnarsson, et al., “Highly Integrated 60 GHz Transmitter and Receiver MMICs in a GaAs pHEMT Technology” IEEE Journal of Solid State Circuits, Vol. 40, No. 11, pp. 2174-2186, November 2005; and K. Niahikawa, et al., “Compact LNA and VCO 3-D MM1Cs using commercial GaAs PHEMT technology for V-band single-chip TRX MMIC,” IEEE International Microwave Symposium, pp. 1717-1720, June 2002, Seattle, Wash.
However, silicon-based technologies always have an edge over them in terms of cost and integration. The introduction of silicon-germanium (SiGe) heterojunction bipolar transistors (HBT), such as those disclosed by J. D. Cressler, in “SiGe HBT technology: a new contender for Si-based RE and microwave circuit applications,” IEEE Trans. Microwave Theory & Tech., Vol. 46, No. 5, pp. 572-589, May 1998, further enhanced the potential of silicon. 60 GHz transceiver circuits using 200 GHz FT 0.12 μm SiGe BiCMOS processes have been demonstrated. See S. K. Reynolds, “A 60 GHz superheterodyne downconversion mixer in silicon-germanium bipolar technology,” IEEE Journal of Solid Stale Circuits, Vol. 39, No. 11, pp. 2065-2068, November 2004 and B. A. Floyd, et al., “SiGe bipolar transceiver circuits operating at 60 GHz,” IEEE Journal of Solid Slate Circuits, Vol. 40, No. 1, pp. 156-167, January 2005.
0.13 μm CMOS has also been used to implement 60 GHz front ends. See C. H. Doan, et al., “Millimeter-Wave CMOS Design,” IEEE Journal of Solid State Circuits, Vol. 40, No. 1, pp. 144-155, January 2005 and C. M. Lo, et al., “A Miniature V-band 3-Stage Cascode LNA in 0.13 μm CMOS,” IEEE Solid Slate Circuits Conference, pp. 322-323, February 2006, San Francisco, Calif.
However, realization of such blocks using 0.18 μm technology has remained a challenge and needs innovative design techniques. There have been examples of 60 GHz transmitter building blocks such as those disclosed by C. H. Wang, et al., in “A 60 GHz Transmitter with Integrated Antenna in 0.18 μm SiGe BiCMOS Technology,” IEEE Solid Stale Circuits Conference, pp. 186-187, February 2006, San Francisco, Calif., for example, using 0.18 μm SiGe BiCMOS process. However, this disclosure focuses on the most critical building block of the receiver, i.e., low noise amplifier development using 0.18 μm SiGe process. It would be desirable to have a simple gain enhancement technique for the millimeter-wave amplifiers to minimize the design complexity.